Radnor Love Triangle Murder-Suicide Focus Of '20/20' Episode

RADNOR TOWNSHIP, PA — A shocking murder suicide in Radnor Township will be the focus of a segment on ABC's "20/20" Friday night.

“20/20” will air the interview with co-anchor Amy Robach and Mark Gerardot, whose wife, Jennair Gerardot, killed his girlfriend and former boss, Meredith Chapman, and then died by suicide.

Chapman and Jennair Gerardot were both found dead in Chapman's home on Lowrys Lane in Radnor's Rosemont section at about 7 p.m. Monday, April 23, 2018.

Not only will Mark Gerardot be featured, local officials, residents, and notables will be on the program.

They include Radnor Police Detective T.J. Schreiber, Sergeant Christopher Four, and Superintendent Christopher Flanagan; Tim Mulvey, Meredith’s former neighbor; Erin McCarthy, The Philadelphia Inquirer reporter who covered the story; Michael Hartman, Mark Gerardot’s best friend since high school; Sheila Brennan, the divorce coach hired by Jennair Gerardot; and Dr. Janice Harper, professional writing coach who is working with Mark on a book about the incident.

Additionally, the show will feature exclusive audio from the listening devices that Jennair Gerardot sewed into Mark Gerardot's clothes to conduct surveillance on him and Chapman.

The program will air at 10 p.m. on Friday, Sept. 6.

Chapman, 33, was shot to dead in her Radnor Township home by Jennair Gerardot, 47, after Chapman and Mark Gerardot were involved in an affair.

Chapman was new to the Radnor area, leaving a job at the University of Delaware to work at Villanova University.

Details of the murder-suicide slowly unfurled in the days following the women's bodies in a home on Lowrys Lane in the Rosemont neighborhood of Radnor Township.

Here's a review of our coverage of this story:

2 Found Dead In Radnor Home
Two female bodies were found with gunshot wounds at a home on Lowrys Lane in the Bryn Mawr section of Radnor on Monday, April 23.

Police Release Details Of 'Calculated' Radnor Murder-Suicide
Meredith Sullivan Chapman, 33, was shot in the head by Jennair Gerardot, 47, of Wilmington, Delaware, Monday night inside Chapman's home on Lowrys Lane in Radnor's Rosemont section, police confirmed. Gerardot then took her own life after killing Chapman, according to authorities.

Ammo, Rubber Gloves Found In Radnor Murder-Suicide Killer's Car
A vehicle was found parked on a side street near Lowrys Lane in Rosemont, where MeredithChapman lived and was killed. After searching the vehicle, authorities recovered ammunition, binoculars, rubber gloves, and ear plugs. Police also found a gas station receipt, which placed Jennair Gerardot in the Radnor area at 2:30 p.m. Monday.Radnor Murder-Suicide

Killer Sought Marriage Help
Jennair Gerardot visited the neighborhood social media site NextDoor pleading for marriage help. Later, Gerardot took to the site again, soliciting recommendations for a marriage counselor.

More Disturbing Details Emerge In Radnor Murder-Suicide
Jennair Gerardot had participated in weapons training and tracked her husband's movements prior to the incident. Before buying the murder weapon, a .357-caliber revolver, she trained to use firearms. Additionally, Gerardot used a tracking device to monitor the movements of her husband Mark Gerardot, which likely led her to find Chapman's home.